The present invention is related to an apparatus and a method for the power supply of auxiliary implements of computers via the bus system of the computer as well as to a method for intelligently starting the computer in case a certain call intended for the computer is received from an ISDN-system.
In modern computers, especially in personal computers and more especially in connection with laptop computers, the requirements with respect to a small as possible power consumption of the computers are becoming steadily more stringened. Due to this for the auxiliary implements of the computer (as well in internal form as cards as for external auxiliary implements, too) increasingly less energy from the bus of the computer is available since with the aim of energy saving the corresponding power packs of the computers increasingly are designed smaller.
Correspondingly the presently valid specifications and recommendations in the area of USB and PC (USB-Spec. 1.2, PC99) are containing very strict demands with regard to the maximal electric power input of auxiliary implements. For example a personal computer from the introduction of the ACPI (advance configuration and power interface) on, e.g. in the sleeping or stand-by mode (suspend mode), only is allowed to consume less than five watts. This has the consequence that an USB-auxiliary implement has to be powered from a separate power source (for example a plug-in power pack) when the power consumption of the implement becomes too high. The PC in this case is not available anymore as a power source. Plug-in power packs however are expensive, take room in the 230 volts multiple socket and the user has an additional cable on the auxiliary implement or the computer.
From the U.S. Pat. No. 5,638,540 an apparatus for the power supply of auxiliary implements of computers via the bus system of the computer already is known in which an energy store is provided in the auxiliary implement, which is supporting the power supply of the auxiliary implement and which by means of a suitable charge circuit is connected to the power supply in the bus system of the computer. In this known device for the power supply however the power supply of the computer constantly is loaded by the charging current.
Followingly it is the task to be solved by the present invention to make it possible to completely avoid the loading of the power supply of the computer by the charging current in cases when the power supply of the computer cannot provide for a sufficient output.
According to the invention this task is solved by the fact that a switching device is provided between the power supply in the bus system of the computer and the charge circuit.
In this connection, preferably the energy store is a storage battery.
Preferably the charge circuit simultaneously can contain a current limiting device for limiting the maximal current intensity drawn from the power supply of the bus system of the computer.
In this connection it is especially preferred to provide a further switching device between the energy store and the power supply of the auxiliary implement and an additional switching device for directly connecting the power supply in the bus system of the computer with the power supply of the auxiliary implement. The auxiliary implement both can directly powered from the power supply of the computer as well as exclusively from the energy store.
In this connection it is preferred that the control of the switching devices is done by a power management system in the auxiliary implement.
It is further preferred in this connection to provide the power supply of the auxiliary implement with a buffer capacitor. In this way voltage fluctuations during the switch-over of the switching devices are avoided.
Further, the task according to the invention is solved by a method for the power supply of auxiliary implements of computers via the bus system of the computer, in which energy is stored in the auxiliary implement, which is used for the buffering of high energy demands of the auxiliary implement and which at a low energy demand of the auxiliary implement or at a higher energy availability in the bus system is supplemented again by directly connecting the power supply of the auxiliary implement at a low energy demand of the auxiliary implement or at a higher energy availability in the bus system with the power supply in the bus system while the energy store simultaneously is connected to the power supply in the bus system and by separating the energy store from the power supply in the bus system at a high energy demand of the auxiliary implement or at a low energy availability in the bus system and by exclusively connecting the power supply of the auxiliary implement with the energy store.
The commands for such connection can be provided by a special micro controller software in the auxiliary implement. By this way an adaptation in the operational system of the computer can be dispensed with.
Further it is a task of the present invention to provide a method for starting a computer connected by an auxiliary implement and a bus system to an ISDN-system from a sleeping or resting mode into an active operational mode, wherein the action of starting the computer only should be triggered in case after a call arriving on the ISDN-system has been determined by the auxiliary implement that the call is actually meant for the particular computer by automatically following a D-channel protocol of ISDN.
According to the invention, this task is solved by the fact that in the auxiliary implement an energy store is positioned, which is supplying the energy for the processing of the D-channel protocol and which, in the sleeping or resting mode of the computer, is recharged from the bus system with a very small current.
In this connection it is especially preferred to recharge the energy store in the auxiliary implement during the active operational state of the computer with a stronger current from the bus system. In this way, constantly a good charging state of the energy store in the auxiliary implement can be ensured.
Further it is preferred to supply the auxiliary implement with current directly from the bus system during the active operational state of the computer. An unnecessary load of the energy store in the auxiliary implement thereby is avoided.